Refrigerating apparatus



May 30, 1933'. CHASE 1,911,432

REFRI GERAT ING APPARATUS Filed Feb. 19, 1930 2 Sheets-Sheet 1 INVENTORBY M Wwfi ATTORNEY May 30; 193;. F. L. CHASE 1,911,432

I REFRIGERATING APPARATUS 2 Sheets-Sheet Filed Feb. 19, Y 1930 INVENTbR$44 ArroR vgy Patented May 30, 1933 UNITED STATES PATENT. OFFICEFBEDERIG CHASE, F DAYTON} OHIO, ASSIGNOR TO FRIGIDAIBE CORPORATION, 01DAYTON, OHIO, A CORPORATION OF DELAWARE I BEFRIGERATING APPARATUSApplication filed February 19, 1930. Serial No. 429,750.

This invention relates to refrigerating apparatus and more particularlyto insulating material and a method of manufacturing said insulatingmaterial for use in the wall of refrigerator cabinets, employingrefrigerating apparatus.

One of the objects of this invention is to will prevent the penetrationof the asphaltic material into the insulating material to anysubstantial degree, thereby preserving the insulating qualities of thematerial.

Further objects and advantages of the resent invention will be apparentfrom the pllowing description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings: Fig. 1 is a perspective view of a refrigerator cabinetembodying features of this invention, Fig. 2 is aview in verticalsection through the refrigerator cabinet;

Fig. 3 is a view in horizontal section on the line 33 of Fig. 2;

Fig. 4 is a perspective view of one slab of the insulating material,and- Fig. 5 is a diagrammatic sectional new on the line 55 of Fig. 4.

In the drawings, I have disclosed a refrigerator cabinet-for the purposeof presenting more clearly the use and purpose of i5 my improvedinsulating material. Thecabinet is shown generally at 10 and includes arefrigerated food compartment 11, the walls of which are heat insulatedto prevent the in-flow of heat to the compartment. This compartment isshown as comprising a metal lining 12 which, for the purposes of thisinvention, may be attached to the framework 13 of the cabinet in anyknown manner. The particular type of cabinet herein disclosed has beendescribed and illustrated in .the copending application of HenryBraeutigam and William C. Holbrook, Se-

rial No. 257,989, filed February 29, 1928, and

reference thereto may be had for a more detailed description of thecabinet and its associated parts.

It should be understood that the metal lining 12 extends around fivesides of the compartment 11, the front being open to allow accessthereto through the door members l4. Slabs of insulating material 15 aresecured to the lining, as more fully disclosed hereinafter. In thisconnection, it should be noted that the boards are cut to conformsubstantially to the shape of the walls, that is, there is a board forthe top, one for each side and one for the bottom. Or, if desired, aplurality of slabs may be used for the walls of the larger cabinets.

The insulating material herein disclosed is a self-sustaining insulatingboard containing as its basic ingredient a substance known as rock ormineral wool. This substance is a' product of rock or slag which hasbeen heated to the melting point, and which has been treated at thattemperature by a stream of. air or steam to form the slag into fibrousmaterial. Many methods for manufacturing this slag or rock wool arealready known, and undoubtedly many new methods will be developed, anyone of which may be used as an auxiliary factor in this invention.

The rock or mineral wool obtained by any known process is then made intoa self-sustaining board. This may also be accomplished in any of theknown ways. For reasons that will be hereinafter more full set forth,however, I prefer to form the sel sustaining board by the process ofcoating the individual rock or slag fibers with an asphaltic orbituminous cement. The treated fibers should then be pressed into thedesired shape and dried to force out the moisture. Or if so desired, themoisture we may be driven off before the treated fibers t as abovedescribed, have been heretofore used in the construction of refrigeratorcabinets. In such constructions great care must be taken to prevent thespoiling of the insulating material which may be caused by condensationof atmospheric moisture within the insulating material, due to the lowtemperature within the compartment, 11. One method of preventing suchspoiling of the insulating material has been to coat the material with apitch-like bituminous cement which may be a refined petroleum producthaving a softening point between 180200 F. This material has beenapplied in various ways. such as for example, by dipping the board intothe hot bituminous cement and thereafter, applying the treated board tothe refrigerator lining. Another method and probably the preferred onehas been to coat the exterior surface of the refrigerator lining 12 withthe pitch.-

like material and then to appl the board to the treated lining. Thereater to comletely seal the insulating material, another ayer of asphalticor bituminous cement has been, heretofore, applied to the wallstructure. By the aid of the drawings, Figures 2 and 3. such aconstruction may be visualized. Therein, the lining 12 is shown ascoated with the asphaltic material 20 to which the slabs of theinsulating boards, made as above set forth, are attached. Around theoutside of the insulating material, a second layer of the asphalticmaterial is shown at 21. It should be noted that the insulating materialis made completely water or moisture proof in that it is completelysealed by the asphaltic material and the frame work of the cabinet.

In actual practice it has been found in cabinets made as above that thebituminous or asphaltio material penetrates into the insulating boardand this invention is concerned with an insulating material which willprevent such penetration.

.It has been found in actual tests that at an asphaltic temperature of375 F., a normal penetration of the asphalt into the insulatlng materialis obtained. By normal penetration is meant a penetration of between and3 g of an inch on each face of the insulating material. Such apenetration amounts in effect to a substantial decrease of efficiency ofthe insulating mate rial since the asphalt is a better conductor. Withhigher penetrations this decrease will obviously be greater and theamount of asphalt necessary to give a satisfactory coatng will also beincreased. In addition, 1t will readily be seen that the actual amountof insulating material necessary will be increased.

To prevent this penetration I have discovered that a solution oremulsion of certain materials such as a starch paste or flour paste isparticularly effective. This may be applied by spraying solutions offlour or starch paste with or without fillers onto the insulating board.The addition'of the filler is not necessary to stop the penetration ofthe asphalt but aids materially in showing just where the material hasbeen sprayed and consequently when a complete covering has beenobtained. In the use of these materials it is, of course, necessary todrive out the 'moisture before coating or applying the hot asphalt. Thismay be accomp ished by heating to a temperature of 300 F. forapproximately 15 minutes.

Such sealing solutions of starch or flour capable of completelypreventing the penetration of hot asphalt may be made up in accordancewith the following formulae.

20 grams flour in 400 cc. cold water 1 gram CuSO. (copper sulfate)fungicide, for preventing fungus growth Heat until it thickens, stirringconstantly.

50 grams Gilders whiting (filler) 500 cc. tap water 150 cc. of solution#1 100 cc. sodium silicate 40 B. 100 cc. 3% starch solution An extremelythin coating, or in fact nothing more than a spray of any of the abovesolutions will prevent penetration of the hot asphalt to a certaindegree, while a good coating will totally prevent such penetration.

applied by means of a spray and the material may be oven dried to driveoff the moisture.

In all cases the above mixtures may be i In Figures 4 and 5, an attempthas been I made to diagrammatically show this step. The insulating boardin the form of selfsustaining material made from rock woolas above setforth is shown at 30 and the coating (greatly exaggerated forillustrative purposes) is shown at 31.

It should be understood that this insulating material, thus treated, maybe applied to the cabinet in either of the two ways setv There are theobjections, however, to emulsified asphalt that if the moisture is notcompletely removed from the coating, there will be a bubbling of the hotasphalt when it is applied over the emulsified asphalt. Then in case theemulsified asphalt is thoroug'hl dried by beat, this heat will cause theemu sified asphalt to soften and it will penetrate into the insulatingboard.

Still another method of preventing the penetration of the asphalt to acertain extent is in the use of a solution of asphalt in mineralsolvents. This remedy is only about as effective as the emulsifiedasphalt, however, and is open to the same objections.

Calcium carbonate in powdered form when sifted over the surface of theinsulating board, will stop the penetration to a certain extent but itis difficult to apply, and results in a rather poor adherence of the hotasphalt to the insulating board.

Sodium silicate solutions are also effective to a certain extent inpreventing the penetration of the asphalt and there is no bubbling whenthe heated asphalt is applied. Sodium silicate is rather diflicult tospray, however, and also has a tendency to crawl on the surface of theinsulating board. This latter defect, however, may be eliminated to acertain extent by the addition of clay or some other collodial agent.

Of all the above substances named, the Hour or starch paste is thepreferred mate- 'rial for preventing the pentration of the asphalt andis particularly desirable when mixed with a filler to indicate when thesurface has been completely covered.

It should be noted that the particular problem, namely the prevention ofthe penetration of the asphalt, is a problem of considerable importanceand that this invention provides a new insulating material and a newmethod of making such an insulat: ing material capable of preventing thepenetration of the asphalt into the insulating material.

\Vhile the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. For a refrigerator including insulating walls, the insulation ofwhich is sealed against the condensation. of moisture therein, a slab ofinsulating material including as its basic constituent, a. rock woolproduct compressed into a self-sustaining form, said product beingtreated with a substance capable of preventing the penetration of thesealing medium into the slab.

2. For a refrigerator including insulating walls, the insulation ofwhich is sealed against the condensation of moisture therein by acovering of asphalt, aslab of insulating material including as its basicconstituent a rock wool product compressed into a selfsustaining formand treated with a substance capable of preventing the penetration ofthe asphalt into the slab.

, 3. For a refrigerator including insulating walls,- the insulation ofwhich is sealed against the condensation of moisture therein by acovering of asphalt, a slab of insulating material including as itsbasic constituent a rock wool product compressed into a self sustainingform and treated with a starch or flour paste capable of preventing thepenetration of the asphalt into the slab.

4. For a refri erator including insulating walls, the insulation ofwhich is sealed against the condensation of moisture therein by acovering of asphalt, a slab of insulating material including as itsbasic constituent a rock wool product compressed into a self-sustainingform and treated with a starch paste containing a filler forpreventllllg the penetration of the asphalt into the s ab.

5. For a refrigerator including insulating walls, the insulation ofwhich is sealed against the condensation of moisture therein, a slab ofinsulating material compressed into a self-sustaining form and treatedwith a. substance capable of preventing the penetration thereinto of thematerial used for sealing the slab.

In testlmony whereofl hereto affix my signature.

FREDERIC L. CHASE;

